Abstract: A modified football helmet has an inner cap attached by elastic straps to the inside of the helmet shell providing a space above the cap. The helmet is further modified incorporating a rigid collar extending outwardly from the bottom of the helmet which has a lower surface positioned a distance above two upright post members extending upwardly from the rigid shoulder pads.

Abstract: An injection molded foam bicycle helmet is disclosed and is constructed from a dome-shaped internal frame and a surrounding coating of a foam based material. The dome-shaped frame is formed from an integrally molded, planar member including an annular lower perimeter body, at least one lateral arc-shaped rib extending from one side of the body to the opposite side of the body, and at least one longitudinal arc-shaped rib extending from the front of the body to the rear of the body. Both the lateral and longitudinal ribs deform out of the plane of the body and into arched configurations, thereby forming the dome-shaped frame. Each lateral rib is also operative to engage each of the longitudinal ribs so as to provide additional structural support for the frame. A number of positioning pins are also formed along the inwardly and outwardly facing sides of the body and the ribs for centrally positioning the frame within the mold.

Abstract: An injection molded foam bicycle helmet and method of constructing same includes a dome-shaped internal frame and a surrounding coating of a foam based material. The dome-shaped frame is formed from an integrally molded, planar member including an annular lower perimeter body, at least one lateral arc-shaped rib extending from one side of the body to the opposite side of the body, and at least one longitudinal arc-shaped rib extending from the front of the body to the rear of the body. Both the lateral and longitudinal ribs deform out of the plane of the body and into arched configurations, thereby forming the dome-shaped frame. Each lateral rib is also operative to engage each of the longitudinal ribs so as to provide additional structural support for the frame. A number of positioning pins are also formed along the inwardly and outwardly facing sides of the body and the ribs for centrally positioning the frame within the mold.

Abstract: A protective helmet assembly (10) comprising a hard ballistic outer shell (12) in a clam shell construction of hinged shell portions (14, 16), the front portion (14) being provided with a window opening (20) and a facial seal (34). A transparent visor (22) and sun visor (24) are pivotally mounted on the shell portion (14) and are positionable to cover the window with a seal (23) between the visor (22) and shell portion (14). Impact absorbing pads (31, 32) of open cell flexible polyimide foam material are attached to the inner surface of the hard shell portions (14, 16) by cooperative fastener strips (35, 36) of hook-and-loop material.

Abstract: A protective hat for children and adults comprises a head-enveloping member constructed of a core of impact absorbent foam, encapsulated within a shell of textile fabric material, the textile fabric material providing the inner and outer surfaces of the hat. The core is so constructed as to provide for conformity to the shape of head of the wearer, and to allow for ventilation. The bulk and density of the foam core is such that in sizes for children, the hat provides significant buoyancy.

Abstract: A bicycle helmet inclueds a helmet body having a plurality of vents, including a front vent that is wider than high. Also, a bicycle helmet includes a helmet body having a plurality of vents, including at least one rear exit port opening outward onto a surface that is below the most rearward margin of the helmet body. Preferred helmets include both such a front vent and a pair of such rear exit ports, and preferred helmets include at least one and more preferably two lengthwise interior channels that may conduct air rearwardly within the helmet over the head of the wearer from the front vent or to the rear exit port or ports, or both from the anterior vent and to the rear exit port or ports. Methods for fabricating a helmet according to the invention include forming the helmet body of two separate parts and affixing the two formed parts together.

Abstract: A high performance sport safety helmet. The helmet is formed by an outer shell adapted for fitting upon a wearer's head, with a frontal periphery defining a centrally arched portion forming a front opening exposing the face and a major portion of the forehead of the wearer. The shell further has a base periphery defining an arcuate base opening for receiving the wearer's neck. A flexible resilient expandable front band is secured to and extends across the front opening of the shell with a substantial portion of the band lying below the centrally arched portion. The band snugly engages and substantially completely covers the forehead of the wearer. An articulated shell liner is secured to and covers the inner surface of the shell. The liner is partially separable and non-detachable from the shell. A visor is pivotally secured to the shell and nestable between the shell and the shell liner for selectively shielding the front opening of the shell.

Abstract: A football helmet and shoulder pad combination are designed to prevent head and neck injuries. An outer helmet is connected to a neck assembly which permits but limits head turning mobility as well as up-down and left and right head tilt. The neck mechanism which is mounted about the neck comprises substantially circular inner and -outer spherical guides and a concentric movable inner element therebetween with an upwardly extending member on each side of the neck. The guides contain stops to limit the motion permitted by the helmet and the lower portion of the mechanism is mounted on the shoulder pads to distribute the load during impact. The helmet portion with a resilient coupling joining the portions. The upwardly extending members on the inner element are mounted to respective sides of the outer helmet. The helmet may also be retrofitted to existing equipment.

Abstract: A protective helmet for bicycles has a skeletal outer body of impact-resistant and impact-absorbing hard synthetic resin and a cushion cap within this body which substantially completely encloses the cranium of the wearer and bridges spaces between the relatively narrow bands from which the skeletal outer body is constituted. The bands include a chin band forming a ring with a occipital band, a frontal band bridging across the chin band and a saggital band centrally connecting the frontal band and the occipital band.

Abstract: A protective helmet, particularly used by children, is provided to include an enclosed, generally cylindrical helmet structure providing a plurality of layers of first and second density polymeric foam respectively, with a chin panel mounted to a first side of the helmet arranged for securement to a second side of the helmet.

Abstract: Novel composites are formed from a low rigidity gelatinous elastomer composition of poly(styrene-ethylene-butylene-styrene) triblock copolymer and high levels of a plasticizing oil. The gelatinous elastomer composition is physically interlocked with an open cell sponge thereby displacing the air space within the sponge and the gel rigidity is found to be greater than about the sum of the combined rigidity of the gelatinous elastomer composition and sponge alone. The gelatinous elastomer composite exhibits a novel combination of properties including unexpectedly high elongation and tensile strength and excellent shape retention after extreme deformation under high-velocity impact and stress conditions. The gelatinous elastomer composites can be made firm or soft and flexible.

Abstract: Novel gelatinous compositions and articles are formed from an intimate melt blend admixture of poly(styrene-ethylene-butylene-styrene) triblock copolymer and high levels of a plasticizing oil.The gelatinous composition is transparent and have a novel combination of properties including unexpectedly high elongation and tensile strength and excellent shape retention after extreme deformation under high-velocity impact and stress conditions. The gelatinous products of this invention are soft, flexible, and have elastic memory, characterized by a gel rigidity of from about 20 gram to about 700 gram Bloom. These and other properties are particularly essential for the gelatinous composition to have utility as toys, therapeutic hand exercising grips, shock absorbers, acoustical isolators, components for cushions, and other uses.

Abstract: A method forms a helmet liner which during its formation is fitted to the head of the user, by forming an inflatable liner element of extensible sheet material approximately conforming to the shape of the interior surface of a helmet shell, providing the element with respective foam filling and vent passages, the vent passages serving to expel air from the liner as foam filling proceeds, mounting the liner element in the helmet on the head of the user, supplying foam to the foam filling passages to inflate the liner element, expel air therefrom and conform the element at an outer surface to the shape of the interior surface of the helmet shell and at an inner surface to the shape of the head of the user, allowing time for curing of the foam admitted to the liner element, and severing parts of the vent and foam filling passages projecting from the liner. The liner element can embrace a forehead portion only of the head of the user or a further element which embraces a rear part of the head can be added.

Abstract: An impact absorbing protective cap includes a rigid shell which fits on the head of the wearer. The shell is generally hemispherical in shape and terminates in a peripheral edge which defines an open space. An attenuator band is mounted to the inner surface of the shell generally at the peripheral edge for distributing lateral impact forces striking the outer surface of the shell. The attenuator band is made of flexible hard material and is in corrugated form with a series of undulations alternately disposed toward and away from the inner surface of the shell.

Abstract: Effective support of the head and neck during high impact accidents or rapid or sudden acceleration or deceleration of riders of motorcycles, skimobiles, jet skis and power boats, is provided by a cervical protection system having a gas-filled bag (110) rapidly deployable from a collar (105) disposed around the base of a helmet (101). When deployed, the bag (110) extends to the mid-sternal area anteriorly, to approximately the fourth or fifth thoracic vertebrae posteriorly, and laterally on the shoulders to a point approximately mid-way between the sternomastoid muscle group and the lateral tip of the scapula, and holds the wearer's head in slight extension to mitigate physical harm. Also, a deployable cervical collar which is removably mounted to a helmet. The collar deployable before or after impact.

Abstract: A protective plastic insert is provided for a conventional golf cap. The insert is substantially hemispherical and is engagable within the cap. The cap is size adjustable. The insert adapts to the size change of the cap. Thus a single size insert fits most golf caps. The shape and hardness of the plastic protect the wearer against the impact of a stray golf ball.

Abstract: Impact protective headgear is disclosed wherein impact protection to the brain case of the skull is at least in part provided by a molded skull enclosing component composed of a relatively thick and stiff cellular polymer material. Provisions are disclosed by which the relatively stiff molded component is rendered size adjustable.

Abstract: A hat of the type having an adjustable headband is provided with a safety liner which includes a lower edge received in the headband. The safety liner has adjustment means for allowing the length of the lower edge to be reduced in response to a circumferentially applied force of the headband. The safety liner includes cut-out sections and is designed to only partially encircle the head of a wearer. A large cutout is provided for location at the rear of the head of a wearer.

Abstract: A helmet has a generally dome shaped helmet body with inner and outer sides and a lower edge extending generally in the shape of a loop; an elongated reinforcement member is embedded in the helmet to extend proximate the looping lower edge portion; that member may have band shape; and additional such band shaped reinforcement members may extend within the dome shape of the helmet. Openings may be provided through the body to pass retention straps, a first strap holder configured to be supported at and by the outer side of the helmet, the holder attached to at least one strap that extends through one of the openings, and the holder operable to transmit strap tension to the helmet. The holder typically holds two strap ends, and defines slots through which the straps pass for adjustable retention by the holder.

Abstract: A protective piece of headgear including an outer cover of conventional appearance in place about and concealing an impact absorbing shell of STYROFOAM or the like. Elongate openings in the shell serve to ventilate the shell and are shaped and sized to prevent golf ball contact with the upper part of the wearer's head. Interchangeable adhesive spacer elements permit the shell to be sized to a wearer's head. Retention of the cover on the shell, either permanently or temporarily, is by a suitable adhesive.

Abstract: A safety helmet includes an outer shell juxtapositionally secured with an inner shell defining an air chamber between the two shells, a plurality of cushioning bellows retained between the two shells, an air-penetrable layer adhered on an inside surface of the inner shell disposed around a wearer's head, and a cap frame sealably combining the two shells and the air-penetrable layer to form a complete safety helmet having a great dampening effect for reducing an external impact force acting upon the helmet by the plurality of cushioning bellows between the two shells for enhancing safety of a wearer of the helmet.

Abstract: A protective headgear conforming to a person's head and capable of absorbing energy. The headgear is constructed of a base member of resilient foam and pad members are secured to the resilient foam. The entire headgear is covered with tough pliable surface casing. The headgear defines a front opening which is generally contoured and shaped to conform with the periphery of a person's eyes and extending downward along the cheek area to expose the chin and neck and two ear openings. A pair of cross members formed on the top of the headgear retain the headgear on a person's head and define ventilation openings.

Abstract: A helmet cooling system has a receptacle containing a coolant through which air flows, impelled by the velocity of the vehicle on which the system is used. The air is ducted from the receptacle to the interior of the helmet. A flexible conduit transmits melted coolant to a mouthpiece within the helmet for refreshing the helmet wearer.

Abstract: An inflatable headband comprising an elongated, strap-like air-bag body covered with a layer of velvet or cotton cloth, having a pair of connecting elements at two opposite ends, a plurality of ring holes made through said air-bag body by the process of heating and sealing or embossed stripes formed on said air-bag body by the process of heat pressing, a pair of spaced eye bars extending from the side edge thereof, and at least one air valve. The air-bag body is inflated and then fastened around the head by the pair of connecting elements. Ornamental items are fastened in the ring holes to make the structure more attractive. The two spaced eye-bars are provided for holding user's eyeglass on the head.

Abstract: A helmet has a generally dome shaped helmet body with inner and outer sides and a lower edge extending generally in the shape of a loop; an elongated reinforcement member is embedded in the helmet to extend proximate the looping lower edge portion; that member may have band shape; and additional such band shaped reinforcement members may extend within the dome shape of the helmet, such as laterally spaced rib or ridge portions.

Abstract: A protective hat comprises a shell having a visor in which the underside of the visor is molded with a textured surface that diffuses reflected light.

Abstract: A helmet has a generally dome shaped helmet body with inner and outer sides and a lower edge extending generally in the shape of a loop; an elongated reinforcement member is embedded in the helmet to extend proximate the looping lower edge portion; that member may have band shape; and additional such band shaped reinforcement members may extend within the dome shape of the helmet. Openings may be provided through the body to pass retention straps, a first strap holder configured to be supported at and by the outer side of the helmet, the holder attached to at least one strap that extends through one of the openings, and the holder operable to transmit strap tension to the helmet. The holder typically holds two strap ends, and defines slots through which the straps pass for adjustable retention by the holder.

Abstract: The invention is directed to a protective helmet comprising a formed plastic foam shell having an internal plastic infrastructure embedded at least partially therein. The embedded infrastructure provides increased shock absorption characteristics for a wearer during use. The helmet can also include either a thin plastic outer microshell or a thicker relatively rigid plastic outer shell, with a padding material attached to the inner surface of the reinforced foam shell, and a retention strap attached to the plastic outer shell.

Abstract: A helmet includes a cap body which is formed of a shell with a buffer liner fitted herein. The cap body further includes a supporting plate secured thereto for covering a lower end face of a front portion of the buffer liner, and a mounting plate fixedly secured to the cover of an inner pad so as to oppose the supporting plate. The supporting plate and the mounting plate are provided 1) with a guide device for guiding a longitudinal sliding movement of the mounting plate between an engaging position and a separating position for defining a predetermined mounting position of the mounting plate with respect to the supporting plate, and 2) with a first locking device for separating and engaging both the mounting plate and the supporting plate in response to the separating position and engaging position of the mounting plate. A rear end of the inner pad is detachably connected to a rear end of the cap body through a second locking device.

Abstract: An infant protection device configured to comfortably yet effectively protect the rear, side and front portions of an infant's head from injury. An alternative embodiment of the present invention additionally provides head protection for the top of the infant's head, as well as for the front, sides and back. The present invention is designed to protect the infant's head during daily activities, such as crawling, walking, and playing, preventing injury due to the infant hitting its head on furniture, floor, etc. The invention is configured and designed such that the child wears it early in infancy, and, becoming used to it, should want to continue to wear the device. The headgear of the present invention may be configured to include such fanciful figures as, for example, mouse or rabbit ears, or other novel designs which may be enjoyed by the child, thereby further encouraging wearing of the protective device.

Abstract: The invention relates to a military safety helmet with a cap resistant to bombardment and an internal band arrangement, connected firmly to the helmet cap at several points and comprised of an approximately horizontally encircling annular supporting band, a plurality of bands extending in a radiating manner from a central fastening piece on the top side of the helmet and bands for connecting the adjacent radiating bands. The internal band arrangement provides all-round impact damping, especially under the effect of shocks, and good ventilation since the bands have formed-on bosses pointing towards the inner face of the helmet cap. Above the supporting band, fastening strips extends which have no bosses and the ends of which are connected firmly to the helmet cap in such a way that the band arrangement rests against the inner face of the helmet cap via the bosses. The radiating bands are approximately the width of the bosses, and the bosses are preferably designed as hollow cylinders.

Abstract: A transparent face shield suitable for exposure to high temperatures, which shield is composed of a pane of polycarbonate having an exterior surface and an interior surface and a layer of gold deposited as a coating in the exterior surface by vapor deposition, together with a plastic inner pane and a PTFE foil interposed between the plastic inner pane and the interior surface of the primary pane such that the inner pane lies flat relative to said the interior surface of the primary pane.

Abstract: An article of laminate construction comprising an underlayer of polycarbonate polymer material 16 to which is applied a chemically resistant outer layer of polysulfone material 17. The layers 16, 17 which are joined by compression-heat molding, are moldable to form the shape of a body protective shell such as a space helmet 10 comprising a shell 18 of polycarbonate, polysulfone laminate construction attached at its open end to a sealing ring 19 adapted for connection to a space suit. The front portion of the shell 18 provides a transparent visor for the helmet. An outer visor 25 of polycarbonate polysulfone polymer laminate construction is pivotally mounted to the sealing ring 19 for covering the transparent visor portion of the shell 18 during extravehicular activities. The polycarbonate under layer of the outer visor 25 is coated on its inner surface with a vacuum deposit of gold to provide additional thermal radiation resistance.

Abstract: A sound-attenuating impact-absorbing earcup comprises a shell having a plurality of generally circular recesses adjacent to the periphery of the cup which function as stiffening contours. The stiffening contours increase the effective stiffness of the earcup shell, improving its sound attenuating capability, and also concentrate applied stress onto those portions of the stiffening contours nearest the point of applied stress. Sufficient applied force causes the shell to fracture in the areas of the stress concentrators, thereby to absorb impact energy in a controlled manner without transmitting it to the head of the wearer. To further enhance its sound-attenuating and impact-absorbing capabilities, the earcup is formed of a low-tensile-strength, high-elongation, high-loss-factor material such as polyvinyl chloride or similar polymer.

Abstract: A single piece, high impact resistant plastic foam helmet having a truncated teardrop shape for aerodynamic efficiency is provided. The helmet design incorporates three ridges centered across the upper front portion of the helmet causing airflow over the helmet to separate from the rear surface of the helmet prior to the onset of turbulence resulting in minimized buffeting of the helmet and reduced drag. A combination of buffeting and a unique retention strap adjustment clip result in greater stability of the helmet on a user's head.

Abstract: A safety helmet comprises a main body, an overbody spaced from the main body to form an air space between the two, an inner body within the main body, primary air vent apertures extending upwardly and outwardly through the inner and main bodies to the air space, and secondary air vent apertures extending upwardly and outwardly through the overbody, so that both the air within the main body, and within the air space between the main and over bodies, will vent by convection when heated.

Abstract: A hard shelled safety helmet comprises a protective rim configuration for the helmet and a shock absorbent liner therefor. The rim extends within a groove formed in the liner.

Abstract: A bicyclist helmet has a outer shell; an inner buffer liner; forward facing baffle controlled air inlets; side baffle controlled air inlets; rear discharge baffle controlled exhaust air outlets; attaching ear cups; attaching fairing cone; attachments and baffles are provided to further enhance the helmet's aerodynamic properties, as well as providing a more comfortable helmet when riding in cold or foul weather.

Abstract: The invention relates to a military safety helmet with a cap resistant to bombardment and an internal band arrangement, connected firmly to the helmet cap at several points and comprised of an approximately horizontally encircling annular supporting band, a plurality of bands extending in a radiating manner from a central fastening piece on the top side of the helmet and bands for connecting the adjacent radiating bands. The internal band arrangement provides all-round impact damping, especially under the effect of shocks, and good ventilation since the bands have formed-on bosses pointing towards the inner face of the helmet cap. Above the supporting band, fastening strips extend which have no bosses and the ends of which are connected firmly to the helmet cap in such a way that the band arrangement rests against the inner face of the helmet cap via the bosses. The radiating bands are approximately the width of the bosses, and the bosses are preferably designed as hollow cylinders.

Abstract: A head-covering device comprising a resilient, adjustable liner, a deformable fabric crown removably attached thereto, and plastic fasteners for removably attaching said deformable fabric crown to said liner, is disclosed. The liner is a single strip of flexible, resilient plastic which is a substantially U-shaped band and which is comprised of a spaced crown, a right arm and a left arm integrally joined to each other, an integrally-formed downwardly-extending cheek piece attached to each of the right and left arms, and a slot separating each of the arms. The liner has a uniform thickness of from about 0.032 to about 0.375 inches, and the internal side-to-side width of from about 4 to about 9 inches, and an internal end-to-end length of from about 6 to about 11 inches. The ratio of the internal length to the internal width of the liner is from about 1.1 to about 2.0. The width of said slot separating the right and left arms of the liner is from about 0.125 to about 1.5 inches.

Abstract: A cushioned helmet structure comprising a helmet shell and liner; and a multiplicity of flexible fins carried by the helmet and projecting generally inwardly relative to the liner to resiliently deflect in bending when receiving loading imposed by the user's head received within the helmet.

Abstract: A forehead guard consisting of a closed loop of a terrycloth or similar stretch material tube and an unattached semi-circular plastic shock-absorbing member within the tube adapted to assume a forehead position on the user while the terrycloth tube is stretched about the back of the user's head to complete the positioning thereof.

Abstract: Apparatus for protecting the wearer of a helmet in the form of an elastomeric cellular helmet cover, encased in an integral shell of like material, that can be attached to the exterior of an unmodified helmet, by means of flexible tabs, to reduce the potential for injury to the wearer. The helmet cover is configured so that it is thicker in the area where impact is customarily greater, and greater resilience is provided at these points. The helmet cover is sufficiently thick at the front to protrude forward at the edge of the helmet and a face guard attaching parts. The wearer is therefore protected and those contacted by the helmet during the game are also protected.

Abstract: A flexible radiation shield apron is disclosed. A characterizing feature of the apron resides in the provision of an encasing fabric sleeve unconnected to the sheets providing radiation resistance, in the areas generally below the waist of the wearer whereby such portions of the apron readily bend with the movements of the wearer. Preferably the sheets providing radiation protection are separated at their peripheries by portions of the encasing fabric sleeve which intrudes between the perimeters of the sheets below the waist further to increase suppleness.

Abstract: A head restraint for the occupant of a vehicle seat is disclosed, which rrains the forward and downward movement of the occupant's head when subjected to large deceleration forces. The restraint includes a strap assembly which encircles the back of the occupant's head and releasably connects to his helmet adjacent to each of his ears at two locations. A retaining strap is slidably connected by a loop to the strap assembly and extends behind the head to a restracting means fixed in the seat. The retracting means pulls the head back against the seat when the deceleration forces exceed a predetermined level, as during flight maneuvers. During normal flight conditions, the occupant is able to move his head freely from side to side as the strap assembly slides through the loop.

Abstract: An energy-absorbing sound-attenuating earcup comprises a rigid shell of an ABS terpolymer that is about 0.090 inch thick so as to crush upon impact at an applied force less than that required to crush the skull of the wearer. The shell has an inner coating of a sound-deadening rubber material to compensate for the reduced sound-attenuating capability of the thinner-than-normal shell. Spaced flanges defining a peripheral channel for receiving a cord of a helmet suspension are formed as staggered series of tabs rather than as circumferentially continuous members to facilitate crushing of the shell upon impact. Resilient earseals disposed between the shells and the wearer's ears comprise first thicknesses of standard polyurethane foam and second thicknesses of slow-recovery polyurethane foam to provide additional impact absorption while permitting the earseals to conform to the wearer's head in cold weather when the helmet is first put on.

Abstract: A helmet with a forward face opening and a downward neck opening comprises a hard outer shell and a custom fittable and split inner shell which fits the head of the wearer without play, is easy to put on and take off, and has a high degree of mechanical stability and provides optimal wearer comfort. For this purpose the inner shell is connectable with the outer shell and it has a fixed inner contour custom fitted to the wearer's head, a one-piece outer shell is slipped over and forms the closure for the inner shell.

Abstract: The present invention is an improved prepreg layer, multilayer composition based on the improved prepreg layer, and article made from the multilayer composite.The prepreg layer of the present invention comprises an array of at least one adjacent, coplanar fibrous element. Each element has a longitudinal axis and each element comprises a plurality of unidirectional coplanar fibers embedded in a polymeric matrix. The fibers are at an oblique angle to the longitudinal axis of the element. The fibers are up to eight inches, preferably from one to eight inches, and more preferably two to six inches long. The adjacent elements are connected by the polymer matrix. Typically, the elements are in strip or sheet form with the longitudinal axis corresponding to long dimension of the strip or sheet. Alternately, the prepreg layer can be a fabric layer, where the fibers are woven or knit and the fibers are at an oblique angle to the longitudinal axis.

Abstract: A protective headgear for boxing and other activities involving direct violence to the head is provided which protects the eyes from direct contact of the padded thumbs and the impacts of blows. The headgear will also provide protection from serious lacerations in critical areas above and around the eyes. The headgear has a multi-layer padded band which extends across the face to cover the upper and lower perimeters of the orbits and the nasal bone. The headgear is fabricated to provide a custom fit by applying component layers to a plaster cast of the face so as to achieve a configuration which will not shift and will afford maximum protection.

Abstract: In a head protector for children and invalids, a series of concentric rings of tubular fabric packed with yieldable material and a top member of yieldable material, and straps binding said rings and top together, a ring of spaced cushions, or pillows, between the lowermost ring and the adjacent ring, and means for positioning said protector on a user's head and maintaining same against rearward movement.